The invention relates to a pump or motor comprising: at least one piston body; a cylindrical housing in which said piston body may reciprocate; a cover for closing of said housing for obtaining a closed compartment between said piston body and said housing; a piston rod connected to said piston body; a shaft rotatably supported by said housing and running in transverse direction in respect of the direction of movement of said piston body; and connecting means located between said shaft and said piston rod for converting either a rotational movement of said shaft into a rectilinear movement of said piston body or a rectilinear movement of said piston body into a rotational movement of said shaft or of a part cooperating with this.
A pump of the type described above can be used for compressing fluids, in particular for obtaining high pressures and when no large volumes have to be transported.
In case of a motor of the type described above a mixture of air and fuel is combusted in the closed compartment by means of a sparking plug, mounted in the cylinder cover. By this the piston body is brought into movement, said movement being converted into a rotational movement of the shaft.
In case of the known pumps and motors the cylindrical housing is usually connected to a crankcase supporting the shaft which is shaped as a crankshaft, and the piston rod is pivotally connected to said crankshaft and to said piston body.
Such a construction is relatively cumbersome because only one end surface of the piston is used and the length of the piston has to be such large that tilting of the piston is opposed as much as possible.
By U.S. Pat. No. 4,013,048 a motor is known comprising two piston bodies provided in two cylindrical housings being in coaxial alignment with each other. Both piston bodies are provided with a piston rod which is fixedly connected to the related piston. The free ends of the said rods are connected to a yoke housing provided with a central slot in transverse direction to the center line of the cylindrical housings, in which slot the crank of a crankshaft is moving. This also brings a cumbersome construction with it as well as an unfavourable loading of some parts of the motor.